Add Hash Function For Set
Add Test For Set Hashing
close #4585
add missing fallback method for rsearch. ref #4586
extend isascii() to strings like other character predicates. ref #4586
remove inbounds from fasta benchmark
Bandaid for #4592, perhaps fixing #4311
Pkg: explicitly detect unknown required packages

Addresses #4049
Pkg: improve "incompatible with fixed" analysis

Addresses #4049

Keeps track of what fixed packages determined the removal
of some package; uses that information in case one of the
required packages was removed in this way.

Also, recursively remove packages from the available list,
i.e. when a fixed package determines the removal of an available
package because its requirements can't be satisfied, then also all
other packages whose requirements can't be satisfied because of this
removal are themselves removed, and so on. (In case of the error
mentioned above, the blame still goes to the fixed packages.)
Pkg: explicitly early requirements check

Addresses #4049

If fixed packages have conflicting requirements, provide
a detailed error message.
Pkg: deepcopy reqs, define it for VersionSets

We need to explicitly copy the Vector inside
VersionSets since it's immutable.
Pkg: code cosmetics
fix some cases where Unreachable needed to be propagated in codegen

specifically, where an error-throwing expression was passed to an intrinsic
remove non-functioning Reverse iterator. closes #4590
reverse ASCIIString, UTF8String, and CharString eagerly. closes #4586

we still use RevString a couple places internally to avoid copies.
a couple release notes updates
Merge pull request #4572 from fundamental/master

Add Hash Function For Set
Merge pull request #4596 from carlobaldassi/pkgerrors

Improved Pkg error messages
Merge branch 'master' of github.com:JuliaLang/julia into jb/de_event_repl